Pixel art is the medium, the tools and not the style. You have to keep in mind where pixel art comes from - games! Those original styles share qualities similar to impressionism. It was a requirement for the art to be minimalistic due to memory limits at the time. It was about limitations and making each pixel convey as much information as possible. Now obviously this isn't so much an issue but I think there are two reasons why people continue to use it now. Time and Aesthetic.
Time is my main reason I use pixel art and it is in the context of games. You can create and change many characters, items, backgrounds, etc and animate them quickly, compared to doing the same thing with more complex art which also takes longer to polish. This is why many independant game developers still use pixel art.
Aesthetic is about personal taste, some people like it, some people not so much. A lot of my favourite games have amazing pixel art sprites where I think the characters look appealing and alive despite the limited sprite details. Aspects of art like shape, colour and gesture still apply and I think it can be very charming seeing it in this minimalistic style. I think it's great that something so simple can have so much character but you might not have this connection to the style, again this is personal taste.
Everyone has different tastes and you seem to be comparing pixel art to different art styles but to me this is a limited way of thinking. You wouldn't look at a sculpture and say it would look better as an oil painting? I hope not, art should be appreciated for what it is, not what it could be.